Don't matter that God is exist or not but what should we believe in. I do because it can help to make the system in the universe. If you want everything should be in the system then you should believe in God. If you want only enjoyment in your life nothing else then you can live free but think at once if anybody will not believe in God, what will be happening.......

As you can see these are just off the top of the head... Seems to me that humans have created a blanket term -> God, and throw just about everything inside of it to describe their lives, lifestyles, fears, beliefs, and egos.

What's worse yet is that they oppress and condemn their brothers and sisters (mankind) into a false worship based on an invisible deity.

I think its important to use logical and rational thinking. If two people pray to god before a challenge, which does god choose to win ?
There will be one winner, but both prayed to god. Does that mean whoever wins, god answered their prayer but not the other! I mean, the winner will thank god, and the loser will not.........